1. Field of Invention
The present invention relates to an electro-optical device, such as an active-matrix driven liquid crystal display device, an electrophoresis device, such as an electronic paper, and an electroluminescent (EL) display device. The present invention also relates to an electronic apparatus and a projection display apparatus, such as a liquid crystal projector, each including such an electro-optical device.
2. Description of Related Art
Electro-optical devices capable of being driven by an active matrix apparatus are known in the related art. The electro-optical devices include pixel electrodes arranged on a substrate in a matrix with thin film transistors (TFT) connected to each pixel electrode, scanning lines and data lines connected to the TFTs and mounted parallel in the columns and rows.
In addition to the above structure, such electro-optical devices include a counter substrate that faces the substrate, a counter electrode that faces the pixel electrodes on the counter substrate, and a liquid crystal layer interposed between the pixel electrodes and the counter electrode so that images can be displayed. The alignment of liquid crystal molecules in the liquid crystal layer appropriately changes by a predetermined potential difference set between the pixel electrodes and the counter electrode so that the transmittance ratio of the light that passes through the liquid crystal layer changes. As a result, images are displayed.
Also, in such electro-optical devices, when potential is applied to the pixel electrodes, a driving method referred to as one H inversion driving, one S inversion driving, or dot inversion driving, may be adopted in order to reduce or prevent the deterioration in the liquid crystal layer. Here, the one H inversion driving is a driving method in which, among the pixel electrodes arranged in a matrix when the pixel electrodes in the nth row are driven by positive potential, the pixel electrodes in the next (n+1th) row are driven by negative potential, so that all of the pixel electrodes arranged in a matrix are driven by applying an electric field whose polarity is inverted every row. Therefore, between the rows of adjacent pixel electrodes, since the direction of the vertical electric field generated between the pixel electrode and the counter electrode is reverse, it is possible to reduce or prevent deterioration in the characteristics of the liquid crystal layer which would occur when the electric field is constantly applied in a uniform direction. Also, the one S inversion driving is a driving method in which the “column” is used as a unit, instead of the “row” being used as a unit as in the one H inversion driving. The dot inversion driving is a driving method in which the electric field whose polarity is inverted is applied to each pixel electrode.
However, according to such driving methods, a reverse tilt domain is generated in each pixel electrode and reverse tilt domains corresponding to adjacent pixel electrodes interact to deteriorate the quality of images. The reverse tilt domain refers to a region where the liquid crystal molecules arranged in a predetermined direction (that is, arranged at a predetermined pre-tilt angle) by an alignment film are arranged in a direction reverse thereto. This phenomenon occurs because an electric field whose polarity is inverted is applied to each pixel electrode to easily disturb the alignment of the liquid crystal molecules. Furthermore, the deterioration in the quality of images due to the reverse tilt domains is seen in the contrast ratio of images, or specifically, a phenomenon in which, when display of light grayscales is seen in an image that should be entirely black, the portions displayed black before remain (in a worst case, black display may remain in a group of horizontal pixels).
Therefore, in the related art devices, in order to cope with such a problem, for example, as disclosed in Japanese Unexamined Patent Application Publication No. 2001-318388, an electro-optical device is provided where the distance between adjacent pixel electrodes and the physical distance between adjacent reverse tilt domains are increased by providing cutout portions in the respective pixel electrodes to reduce or prevent the deterioration in the quality of images.